Sensory Evaluation and Consumers’ Willingness to Pay for Quality Protein Maize (QPM) using Experimental Auctions in Rural Tanzania

The purpose of this study was to evaluate the sensory characteristics and consumer acceptability of quality protein maize (QPM) in rural Tanzania. Due to the malnutrition problem facing consumers in developing countries, QPM which has almost double the amount of tryptophan and lysine, has been identified as a possible solution to this problem. To know whether consumers will accept QPM, it is vital that its sensory attributes and consumer acceptance tests are carried out. Sensory characteristics were determined using home use testing and central location methods by use of stiff porridge. Three districts were visited and 120 consumers participated in home use testing, whereas 30 respondents participated in the central location testing. At the central location, triangle test was also undertaken to find out if a difference exists between QPM and conventional maize. Additionally, acceptability of QPM was tested using BDM method. Consumer characteristics of QPM were highly appreciated for stiff porridge, a major maize product in East Africa. This was observed both in home use and sensory location testing. Likewise, consumers were willing to pay more for QPM than for conventional maize in all evaluation criteria used. Triangle test showed a significant difference between QPM and conventional maize. Sensory evaluation however needs to be repeated with other QPM varieties to ensure that it is not only a specific QPM variety that has favourable consumer characteristicsQPM, consumer acceptability, sensory evaluation, malnutrition, Tanzania, Crop Production/Industries, Demand and Price Analysis,

Engineering of spatial solitons in two-period QPM structures

We report on a scheme which might make it practically possible to engineer the effective competing nonlinearities that on average govern the light propagation in quasi-phase-matching (QPM) gratings. Modulation of the QPM period with a second longer period, introduces an extra degree of freedom, which can be used to engineer the effective quadratic and induced cubic nonlinearity. However, in contrast to former work here we use a simple phase-reversal grating for the modulation, which is practically realizable and has already been fabricated. Furthermore, we develop the theory for arbitrary relative lengths of the two periods and we consider the effect on solitons and the bandwidth for their generation. We derive an expression for the bandwidth of multicolor soliton generation in two-period QPM samples and we predict and confirm numerically that the bandwidth is broader in the two-period QPM sample than in homogeneous structures.Comment: V1: 15 pages, 8 figures. V2: Accepted for publication in Optics Communications.16 pages, 10 figures. New soliton content figures, confirming the theoretically predicted peak splitting in 2-period QPM, have been include

Breeding Quality Protein Maize (QPM): Protocols for Developing QPM Cultivars

This manual is intended for maize breeders who would like to start developing quality protein maize (QPM) cultivars. It is a compilation and consolidation of several breeding protocols successfully used at CIMMYT over two decades of QPM development and breeding. A brief background and the basic theory of QPM genetics are explained, leading up to detailed methods and procedures of QPM development.Zea mays, Plant breeding, Breeding methods, Genetic resources, Protein quality, Protein content, Application methods, Lysine, Tryptophan, Food composition, Crop Production/Industries, F30, Q04,

Evaluating the Impact of Biofortification: A Meta-analysis of Community-level Studies on Quality Protein Maize (QPM)

Biofortification, or the genetic improvement of the nutritional quality of food crops, is a promising strategy to combat undernutrition, particularly among the rural poor in developing countries. However, traditional methods of impact assessment do not apply to biofortified crops as little or no yield increases are expected. Significant progress has been made to develop maize varieties with improved protein quality, collectively known as quality protein maize (QPM). Evidence for the impact of QPM at the community level, as demonstrated by randomized, controlled studies, was evaluated using meta-analysis. A new and generalizable effect size was proposed to quantify the impact of QPM on a key outcome, child growth. The results indicated that consumption of QPM instead of conventional maize leads to an 8% (95% CI: 4-12%) increase in the rate of growth in height and a 9% (95% CI: 4-12%) increase in the rate of growth in weight in infants and young children with mild to moderate undernutrition from populations in which maize is a significant part of the diet. These results are the first step in evaluating the potential economic impact of QPM by establishing and quantifying a link between use of the improved crop and nutritional outcomes. QPM can serve as a model for other biofortification efforts, and in particular, the conceptual framework and methodologies for impact assessment are directly applicable to other biofortified crops.Impact assessment, biofortification, meta-analysis, Crop Production/Industries, Food Security and Poverty,

Extension and adoption of biofortified crops: Quality protein maize in East Africa

Biofortified crops, bred for improved nutritional quality, can alleviate nutritional deficiencies if they are produced and consumed in sufficient quantities. These varieties can be promoted based on their agronomic performance or based on their nutritional qualities. Quality protein maize (QPM) was the first biofortified crop and has been disseminated in Africa using both approaches. To study their effectiveness, a survey of rural households was conducted in the maize-growing areas of East Africa, comparing communities with access to QPM extension activities to control communities. The results show that a third to one half of the farmers in project communities participated in extension activities in all countries except Kenya. In these communities, familiarity with QPM was high (74-80% of farmers), again except for Kenya (19%), but understanding of their nutritional benefits was much lower (47-55%, with 7% in Kenya). In all countries, farmers evaluated QPM varieties as good or better than conventional varieties (CV) for post-harvest characteristics. For agronomic characteristics, however, QPM varieties scored better than CV in Uganda, about the same in Tanzania, but less in Ethiopia. Adoption patterns differed widely between the countries: in the project areas it varied from 70% in Uganda, 30% in Tanzania to none in Kenya. In the control areas, adoption was only observed in Uganda (45% of farmers). Factors that significantly influenced adoption were farmers’ participation in extension activities, farmers’ agronomic and post-harvest evaluation of QPM vs. CM, and their understanding of the nutritional benefits of QPM. Evaluation for agronomic performance was found to be more important than knowledge of nutritional benefits, thus favoring the first approach. A reliable seed supply was, however, found to be a basic condition for adoption.Teaching/Communication/Extension/Profession,

Multistep Parametric Processes in Nonlinear Optics

We present a comprehensive overview of different types of parametric interactions in nonlinear optics which are associated with simultaneous phase-matching of several optical processes in quadratic nonlinear media, the so-called multistep parametric interactions. We discuss a number of possibilities of double and multiple phase-matching in engineered structures with the sign-varying second-order nonlinear susceptibility, including (i) uniform and non-uniform quasi-phase-matched (QPM) periodic optical superlattices, (ii) phase-reversed and periodically chirped QPM structures, and (iii) uniform QPM structures in non-collinear geometry, including recently fabricated two-dimensional nonlinear quadratic photonic crystals. We also summarize the most important experimental results on the multi-frequency generation due to multistep parametric processes, and overview the physics and basic properties of multi-color optical parametric solitons generated by these parametric interactions.Comment: To be published in Progress in Optic

Coupling quasi-phase matching: entanglement buildup in χ(2)\chi^{(2)} nonlinear waveguide arrays

Wavevector quasi-phase matching was devised in the 1960s as a way to boost nonlinear interactions with efficient quantum noise squeezing as one outstanding outcome. In the era of quantum technologies, we propose a new coupling quasi-phase matching for efficient generation of multimode downconverted quantum light in nonlinear waveguide arrays. We highlight this technique achieving multimode quantum entanglement and Einstein-Podolsky-Rosen steering buildup. We discuss the feasibility of this method with current technology and demonstrate its competitiveness as a resource for continuous variables quantum information.Comment: 9 pages, 5 figures, v2 closer to published versio